Monday, January 30, 2017

Honestly, for me it's not the improved glucose management, but rather the proof that you must not use antibacterial mouthwash that's the takeaway, here.

What? Yes, the use of mouthwash can ruin all beneficial effects of nitrate containing foods - those on your blood pressure, those on your pump and - as a recent study from the Colorado State University indicates - even the beneficial effects the co-ingestion of beetroot juice with carbohydrates will have on obese individuals' glucose tolerance.

Oh, you're not obese? Well, in that case, the effect is not going to reach statistical significance, but since it's not going to be zero and you can learn something about the incompatibility of your nitrate-based pre-workout performance enhancingpump supplement and antibacterial mouthwash, it's still worth reading the rest of today's SuppVersity article.

At first, it may be odd that a "pump supplement" or "blood pressure regulator" is able to improve one's glucose handling. If we take into consideration that insulin resistance and obesity are characterized by low nitric oxide (NO) bioavailability, however, and know that nitrate the consumption of dietary nitrate (NO3−) increases NO formation, via NO3− reduction to nitrite (NO2−) by oral bacteria, the observations Joseph W. Beals and colleagues made in their latest study do no longer seem that odd.

Figure 1: Schematic of experimental visits. Two modifed oral glucose tolerance tests were administered, on two separate occasions, in a random order. At the start of one visit, participants completed 3 × 1 min mouthwash regimen. Without delay, they then ingested beet juice supplemented with glucose within 5 minutes. Venous blood was sampled repeatedly over 120 minutes and analyzed for concentrations of glucose and insulin. See text for more details (Beals. 2017).

And that's the case for both, (a) the observation that the co-ingestion of dietary nitrate (beet juice) with 25g of glucose (with the CHOs in the juice that's 75 g of total carbohydrates), significantly improved the glucose tolerance of the study's 10 obese adult subjects (34.0 ± 0.8 kg/m²).

No, this is no outlier study: Only recently Vasconcellos et al. (2017) were able to prove that the administration of 100g of a nitrate-rich beetroot gel did not significantly improve their young, trained subjects' running performance, but reduced their blood glucose levels by a statistically significant 10% - and don't worry that's not going to give you hypoglycemia, after all that's the glucose level at the anaerobic threshold and thus when stress, gluconeogenesis and the digestion of the CHO-containing gels will increase your glucose levels (see Figure on the left). In other words: It's "just" further evidence of the beneficial effects of nitrate on glucose management.

And it also led to small but visible improvements in the 12 non-obese study participants (body mass index: 26.3 ± 0.8 kg/m²), and (b) the revelation that inhibiting the nitrate NO3- to nitrite NO2- reduction in the mouth by the prior use of antibacterial mouthwash blunted the effects.

While the co-administration of 500 mL of beet juice (BJ | Biotta, Carmel, Indiana, USA), estimated to contain approximately 17 mmol of nitrate, has only marginal effects in lean individuals (who usually don't suffer from reduced NO2-availability), it has practical relevant effects on the glycemia of obese adults, potentially NO2-deficient adults at risk of developing insulin resistance of whom Beals et al. highlight that they may see significant benefits from ingestion of healthy nitrate-rich foods during meals... as long as they stay away from anti-bacterial mouthwash (MW) in form of one 60s rinse with 10 mL of 1.5% H2O2 (Peroxyl; Colgate Oral Pharmaceuticals, Inc., New York, NY) followed by two 60s rinses with 10 mL of antibacterial mouthwash (chlorhexidine digluconate; Corsodyl, BCM Ltd., Nottingham, UK), that is.

So, what do you have to remember? Firstly: If you're obese or working with overweight / obese clients you can use nitrate-rich foods such as beetroot juice to improve your or your clients' glucose management.

What I would not suggest is to guzzle 500ml beetroot juice with every meal. After all, that's going to add 50g of carbs and thus 200kcal to every meal. The small but significant increase in glucose handling clearly isn't worth that. Choosing meals with a high(er) nitrate content (e.g. meals rich in leafy greens, rhubarb, lettuce, beans, bulb vegetables like garlic and onions, fruiting vegetables like eggplant and squash etc.), on the other hand, should yield similar benefits without extra-kcals.

Secondly: Even if you're lean you can, albeit to a sign. smaller extent, benefit from including high nitrate foods in your meals. After all, another glimpse at Figure 1 reveals that the ridged line with circles that illustrates the postprandial glucose levels after co-ingestion of beetroot juice without the prior use of mouthwash (and thus allowing for the nitrate benefits to unfold) is constantly below the corresponding solid line for the beetroot + mouthwash trial.

Thirdly: We must not forget that the study at hand also signifies that anyone who consumes nitrate supplements to increase his pump, lower his blood pressure or increase his performance, should avoid antibacterial mouthwash (or toothpaste) at least in the vicinity of nitrate consumption to ensure that the important reduction of NO3- to NO2- can even take place | Comment!

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